Send only latest jobs in pipeline webhook payload

What does this MR do?

Changes the pipeline webhook payload to send only latest jobs.

https://gitlab.com/gitlab-org/gitlab/-/issues/300159

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content